Sewing machine with looper thread control



June 2, 1933-v F. EBER-r SEWING' MACHINE WITH'LOOPER THREAD CONTROL mama@ Filedmugfle, 1936I 5 sheets-sheet 1 June 211, w3. y F, IEem 2,121,689

SEIWINC` MACHINE WITH LOOPER THREAD CONTROL Filed Aug. Vla, 1936 5 sheets-she@v 2 l l t0 9 35 o s Lm 2E, 193. F. EBERT SEWING MACHINE WITH4 LOOPER THREAD CONTROL v Filed Aug. 18, 1936 5 snets-sheevt s mw. www

I June 21,193. HEBER-f 5 Sheets-Sheet 4 Filed Aug. 18,- 1936 Patented` June 21, 1938 UNITED STATES 2,121,689 SEWING MACHINE wl'rn LooPEa THREAD coN'r ROL Fritz Ebert, Oberndorf-on-the-Neckar, Germany,

assignor to Manset-Werke A.G., Oberndorfon-the-Neckar, Germany, a joint-stock company of Germany Application August 18, 1936, Serial No. 96,680 In Germany September 2, 1935 13 Claims.

This invention relates to a sewing machine with looper thread control and take-up device,

55 termediate sham, which is provided in the maand has for its object to control the looper thread in such fashion that the same is in a tensioned condition in every phase of the sewing operation.

For this purpose, in accordance with the invention, a control element in conjunction with the pull-off means and a thread clamping means co-operates in such fashion with a cast-off and thread guides that the looper thread is stored by the control element immediately it is released by the looper .or the pull-off means. The control element preferably comprises two curved portions, each of which oscillates between a fixed thread guide and the fixed cast-off. The curved members are moved in common by a lever, which 1s mounted on an intermediate spindle that at the same time acts as operating spindle for a cutting device provided on the machine.

According to an additional feature of the invention, the pull-off device for withdrawing the thread from the source is united in such fashion with the looper thread control device that the lever operating the curved members at the same time actuates the pull-off means, a pull-off `hook being mounted on the lever to be adjustable. This hook swings between two fixed thread eyes.

The cast-olf and the thread guides are adjustable independently of each other for the purpose of being able to regulate the quantity of thread takenup by the curved members. To facilitate the introduction of the thread into the thread guides the latter are provided on a stirrup, which is furnished with a handle-like abutment and is capable of being rocked out of the range of the pair of curved members and the cast-oit. In the operative andthe inoperative positions the stirrup is locked by a spring or the like moving into a notch. In the operative' position the stirrup may also be readjusted in its elevation. In order that when the stirrup is moved over the threaded looper thread is immediately conducted into the correct position with respect to the castoi and does not become intercepted, thereis provided on the cast-off a horn which guides the thread accordingly.

The thread clamp co-operating with the looper thread control means ensures that upon the taking up of thread from the source thread is also not withdrawn. by the control element. The thread clamp conveniently comprises two fixed springs,which are compressed rhythmcally during the sewing operation by the end of a rocking lever. The rocking lever is operated by an in- (Cl. i12- 241) chine frame for the main feed, by means of a connecting rod which is adjustable in length, in which connection the time of clan ping and the amount of pressure applied to the two springs may be varied. yProvision is also made for an` additional possibility of regulating the thread clamping means by an adjustable screw, which is located at the effective end of the rockinglever.

The arrangement as described acts particularly favourably by the fact that owing to a gentle regulation of the thread and extensive adaptation to the particular thread employed the machine may be operated at a higher speed and with diminished tendency to breakdown even in the case of an inferior thread.

In the drawings the invention is illustrated in conjunction with a sewing machine of the supporting arm type having a cutting device. It is, however, not limited to machines of this description, but may be applied literally to any desired type of sewing machine having a looper mechanism.

In the drawings Y Fig. 1 is4 an elevation in partial section of the frame of a sewing machine furnished with a cutting device, with an arm enclosing the looping device.

Fig. 2 is a cross-section of the arm taken along the line II-II in Fig. 1.

Fig. 3 is a plan view of Fig. 1, partly in section, with the top of the arm removed.

Fig. 4 shows a detail of the looper thread control.

Figs. 5 to 16 illustrate the function of the looper thread control and take-up mechanism according to the invention in four "ierent positions, Figs. 5, 8, 11, and 14 showing the devices themselves, whilst to facilitate comprehension Figs. 6, 9, 12

and 15 are front views of the particular needle and looper' positions corresponding with Figs. 5, 8, 11 and 14. Figs. 7, 10, 13 and 16 are the appertaining needle and looper positions viewed from the side, partly in section.

In the frame i of the sewing machine there is mounted ,the main shaft 2 which is furnished with a hand-wheel 3 anddrives the needles through the medium of a device of desired kind (not shown). From the main shaft 2 there is also derived the drive for the looper and the material feeder, which drive, since the same may be of the usual construction, will not be particularly described. Further, the main shaft 2 also drives in immediate fashion the mechanism for actuating the cutting device. For this purpose there is provided on the main shaft an eccentric 4 having a lever arm 5 which is engaged through the medium of a spherical screw 6 by a link 1, the other end of which is connected by According now to the invention, the drive for the looper thread control is also derived from the spindle 9. A lever I3, which in the same manner as the lever I8 serves as collar to limit the lateral movement of the spindle 9, is mounted on the spindle 9 in such fashion that it participates in the oscillations of this spindle. At the free end of the lever I3 there is guided yand securedon either side in a groove I4 a curved member I5 and I6, which members control the looper thread in a manner which will be described more fully later. The curved members are so constructed that the thread sliding along the curve cannot be intercepted. For this purpose both curved mem-.- bers possess at their upper end a projection I1, whichV prevents the thread from falling on towards the rear. The intermediate space of these two curved members is engaged by a cast-olf I8, which is rmly secured to the supporting arm II and can be adjusted only in the longitudinal direction, the same projecting to a greater or smaller extent into the space between the curved members. On the supporting arm II there is also provided aA holder I9 which is likewise adjustable and xable in the longitudinal direction, and on this holder I9 there is mounted a lever 20 carrying a stirrup 2I having two thread eyes 22, which stirrup engages about the curved memv bers I and I6 and the cast-off I8. 'I'he lever 28 the source.

may be rocked upwards about the pin 23 and is held both in the operative position as well as in the oscillated position by a notch engagement which may comprise a spring snapping into either the notch 24 or the notch 25. r By the rock' ing of the stirrup 2l out of the range of the curved members and the cast-01T into the vertical position the threading of the yarn in the thread guide is greatly facilitated, and for the purpose of better manipulation the one arm of the stirrup possesses a handle-like abutment 28. In the horizontal operativeposition the lever 20 is made to be adjustable by means. of a regulating screw 21 provided thereon, which bears against a iixed portion of the supporting lframe. In order now to prevent the thread passed through'the eyes 22 from being caught against the cast-oil when the stirrup 20 is moved over the cast-oil is furnished with a horn 28 which guides the thread along the cast-off and causes it to move into the proper position.

'Ihe thread pick-up lever I3 carries at the same time"the device for drawing oii the looper thread from the source. A thread pull-off hook 29, which is mounted to be adjustable and xable in an eye 30 in the lever I 3, co-operates by means of its free end with two thread eyes 3I provided on the supporting arm II. the same performing with the lever I3 an oscillatory movement by means of which the thread is drawn oil from 'I'he hook 29 accordingly acts as preliminary take-up means. In order to prevent this preliminarytake-up means from also drawing oi thread from the looper there is provided between the hook and the control curve 4a thread clamping-means 'whichis ,constituted by two thread-tensioning springs 32 and 33 tlrmiy mounted on the frame I, between which there passes the looper thread and which may be pressed together for rmly holding the thread. 'I'he drive for the mechanism is derived from an intermediate shaft 34, on which there is mounted a lever 35 that operates through vthe medium of two spherical screws 36 and a longitudinally adjustable connecting rod 31 having a left and right hand thread, a double lever 38 which rocks about a bolt 39 'mounted in the supporting arm II. With its free end the double lever 38 presses at the proper time the thread tensioning spring 32 against the thread tensioning spring 33, the intermediately disposed thread being so clamped that no thread can be withdrawn from the looper. An adjustment screw 40 on the free end of the double lever 38 permits of a fine adjustment, by means of which the relative pressure of the tensioning springs may be regulated, and the adjustment screw is held in position by a screw 4I. Behind the thread clamp there is provided an additional eye 42, which may be integral with the eyes 3|.

The looper thread 43 is conducted from the source through the tube 44 to the eyes 3l, between which there swings the hook 29 of the preliminary take-up means, and passes through the thread clamp to the eye 42,-from where it reaches the eyes 22 of the stirrup 2I and is then conducted to the looper. The looper thread control means operates, therefore, according to the invention as follows:-

' Proceeding from the position of the needles and the looper as shown in Figs. 5 to 7, the lever I3, upon the reversal of the needles from their lowest position, whereby the looper has reached its extreme left hand position and again swings towards the.` right, is also at the point of reversal of its oscillatory movement. In this position thread has been drawn off from the source by the pullzof means 29 and the thread clamp has again been opened. The two curved members I5 and I 6 commence to swing upwards, and in co- `operation with the cast-off I8 and the two thread eyes 22 they take up the thread released by the looper and the pull-01T means until the looper thread has reached the extended position (Fig. On its additional movement towards the right (Fig. 9) the looper no longergives oil' thread but from this point on uses thread. In the meantime the lever I3 continues to swing upwards with the two curved members (Fig. 8), the pull-oi means letting ofi a certain amount o1' thread. At the end of the upwards movement of the lever I3 it then releases an additional amount of thread for the looper by way of the curved members I5 and I 6 (Fig. 11), at which point both the needles as Well as the looper have reached their extreme positions (Fig. 12 'and Fig. 13). 'The needles again move downwards, the looper swings to the left, and the thread pick-up lever I3 with the curved members likewise swings downwards. The thread which is again liberated upon the return of the looper is taken up by the curved members I5, I6. For this purpose the prole of the cast-oil I8 is so formed on the inside that the thread remains hanging on an upper hump of the cast-oil (Fig. 11) until it slides in front of the foremost projectory part of the curved member, i. e., all thread released by the looper has been taken' up by the curved member. It is not until then that the thread upon additional movement of the lever I3 downwards is pressed against the lower side of the projection (Fig. 14). In the meantime the looper thread has again reached an extended position (Figs. 15 and 16), and upon its additional movement towards the left it commences to consume the thread stored by the curved members, where` by the curved members release the thread accordingly. Upon the commencement of the downward movementI of the lever I3 the pull-oli' hook 29 in respect of the pull-off means enters into operation, whereby the thread clamp 32, 33 is closed and rmly 'holds the thread disposed between the same, so that the preliminary pulloff means can only draw. off new thread from the source. Initially the thread remains hanging against the lower side of the projection on the cast-off I8 until upon the additional downwardl movement of the lever I3 it is again able to swing upwards by reason of the receding profile of the curved members I5 and I6 (Fig. 5) and remains hanging against the upper side of the hump on the cast-off I8. The movement of the looper towards the left (Figs. 15, 6) has consumed the pull-ofi` means for the looper thread, a threadA threadliberated by the curved members.

The co-operation of the two curved members I5 and I6 and the cast-01T I8 within the thread guides 22 of the stirrup accordingly takes-place by reason of the form of the curved members and the cast-off in such fashion that the looper thread is subjected to a slight tension in every position of the looper, i. e., at no time sags and is able to be caught at any point.

Having now particularly described and ascertained the nature of my said invention, and in what manner the same is to be performed, I declare that what I claim is:-

, 1. In a sewing machine, a looper, a preliminary pull-off means for the looper thread, a thread clamp, a fixed cast-off and thread guides, and a control element in conjunction with the said pullof means and the thread clamp comprising two curved portions each adapted to oscillate between the said cast-oftand a fixed thread guide, and a transverse axle having a lever on which the control element and the pull-off means are mounted, the said pull-off means 'being driven bythe oscillatory motion of the said lever.

2. In a sewing machine, a looper, a preliminary pull-oi means for the looper thread, a thread clamp, a xed cast-off and thread guides, and a control element in conjunction with the said pull-01T means and the thread clamp comprising two curved portionsleach adapted to oscillate between the cast-olf and a fixed thread guide, a transverse axle having a lever on which the control element and the pull-off means are mounted, and a pull-off hook on the said lever co-operating with two fixed thread eyes.

3. In a sewing machine, a looper, a preliminary clamp, a fixed cast-off and thread guides, and a control element in conjunction with the said pulloif means and the thread clamp comprising two curved portions each adapted to oscillate between the said cast-off and a fixed thread guide, a transverse axle having a levergon which the control element and the pull-oi means are mounted, a longitudinally adjustable pull-off hook on the saidlever, and a screw for securing the said hook in its adjusted position.

4. In a sewing machine, a looper, a preliminary pull-oil means for the looper thread, 'a thread clamp, a castet and thread guides, and a control element in conjunction with the said pull-off means and the thread clamp co-operating with the said cast-off and thread guides, a transverse axle having a lever on which the control element and the pull-oi lmeans are mounted, the said v clamp, a fixed cast-off, a stirrup, thread guides mounted on the said stirrup, a screw for adjusting the said stirrup in height, a control element in conjunction with the said pull-off means and the thread clamp co-operating with the said castoif and thread guides, and a transverse axle having a lever on which the control element and the pull-off means are mounted, the said control element storing the thread immediately it is released by the said looper or preliminary pull-off means to prevent it from sagging.

6. In a sewing machine, a looper, a preliminary pull-oi means for the looper thread, a thread clamp, a fixed cast-01T and thread guides, a control element in conjunction with the said pull-off means and the thread clamp comprising two curved portions each adapted to oscillate between the said cast-oi and a xed thread guide, a transverse axle having a lever on which the control. element and the pull-off means are mounted, a stirrup supporting the said thread guides and disposedv normally within range of the said curved members and the said cast-off but capable of being rocked out of this position to facilitatethreading of the guides, and a handle-like abutment for manipulation of the said stirrup.

7. In a sewing machine, a looper, a preliminary pull-off means for the looper thread, a thread clamp, a,xed cast-o and thread guides, a stirrup supporting the said thread guides and movable to operative and inoperative positions, a control element in conjunction with the said pull-off means and the thread clamp co-operating with the said cast-oi and thread guides, a transverse axle having a lever on which the control element and the pull-01T means are mounted, and means for locking the said stirrup in its operative and inoperative positions.

8. In a sewing machine,` a looper, a preliminary pull-off means for the looper thread, a' thread clamp, a fixed cast-off, a stirrup, thread guides mounted on the said stirrup, a. control element in conjunction with the said pull-off means and the thread clamp comprising two curved portions each adapted to oscillate between the said castoi and a ,fixed thread guide, a transverse axle having a lever on which-the control element and the pull-ofmeans are mounted, the said stirrup being disposed normally within range of the said curved members and the said cast-off but capable of being rocked out of this position to facilitate threading of the guides, and a spring co-operating with a notch for locking the said stirrup in its operative and inoperative positions.

9. In a sewing machine, a looper, a preliminary pull-off means for the looper thread, a thread clamp. a xed cast-off and thread guides, a control element in conjunction with the said pu11.

being rocked out of -this position to facilitate threading of the guides, and a guiding horn on the said cast-off for correctly placing the thread when the said stirrup is moved into the operative position. y

10. In a sewing machine, a looper, a preliminary pull-oi means for the looper thread, a thread clamp comprising two springs secured /to the frame of the sewing machine and a lever pressing the said springs together, a cast-off and thread guides, a control element in conjunction with the said pull-oil? means and the thread clamp co-openating with the saidcast-oi and thread guides# the said control element storing the thread immediately it is released by the said looper or preliminary pull-off means to prevent it from sagging and a transverse axle having a lever on which the control element and the pullofE means are mounted. Y

11. In a sewing machine, a looper, a preliminary pull-oir means for the looper thread, a thread clamp comprising two springs secured to the frame of the sewing machine and a rocking lever pressing the said springs together, a connecting rod connecting the said rocking lever with a main shaft of the sewing machine, a castoi and thread guides, and a control element in conjunction with the said pull-off means and the thread clamp and co-operating with the said cast-oi and thread guides, a Ytransverse axle having a lever on which the control element and the pull-ofi` means are mounted, and means for varying the time of clamping and the amount of pressure exerted by the said lever on the said springs;

12. In a sewing machine, a looper, a preliminary pull-ofi' means for the looper thread, a thread clamp comprising two springs secured to the frame of the sewing machine and a rocking lever pressing the said springs together, a connecting rod connecting the said rocking lever with a main shaft of the sewing machine, a castoi and thread guides, a control element in conjunction with the said pull-oir means and the thread clamp co-operating with the said cast-olf and thread guides, and a transverse axle having a lever on which the control element and the pull-off means are mounted, the said connecting rod being longitudinally adjustable for the purpose of varying the time of clamping and the amount of pressure exerted by the said lever on the said springs. n

13. In a sewing machine, a looper, a preliminary pull-off means for the looper thread, a thread clamp comprising two springs secured to the frame of the sewing machine and a rocking lever pressing the said springs together, a longitudinally adjustable connecting rod connecting the said rocking lever with a main shaft of the sewing machine, a cast-off and thread guides, a control element in conjunction with the said pulloi means and the thread clamp co-operating with the said cast-01T and the thread guides, a transverse axle having a lever on which the control element and the pull-oir means are mounted, a regulating screw' on the said rocking lever for iine adjustment purposes, and a second screw locking the said rst screw.

'FRI'I'Z EBERT. 

